Reviewed by Preeti Subramanian, PhD
Obesity is associated with myriad health risks ranging from heart disease and type 2 diabetes to sleep apnea and stroke. Now, a new study has linked it to age-related macular degeneration
Stress on the body from obesity can make people more likely to develop age-related macular degeneration, even if they have returned to a normal weight, a Canadian study found. The findings support the notion that committing to a healthy lifestyle early in life can help avoid age-related macular degeneration.
The study, published in the prestigious journal Science and led by BrightFocus grantee Dr. Przemyslaw Sapieha and Dr. Masayuki Hata from the Maisonneuve-Rosemont Hospital Research Center and the University of Montreal, describes how stressors on the body can reprogram the cells of the immune system. These cell changes can damage the eye and lead to age-related macular degeneration-like lesions.
The immune system keeps the body healthy. Immune system cells become activated when they fight pathogens such as bacteria and viruses. But they also become activated when the body is exposed to stressors, such as excess fat in obesity. These inflammatory cells can travel to other parts of the body, including the eye, where they spark changes that promote age-related macular degeneration.
These findings provide key insight into the role of immune cells in age-related macular degeneration. In the study, obesity was used as a model to accelerate and exaggerate the stressors incurred on the body throughout life. But the researchers noted that other types of stressors could play a similar role. For example, anxiety is known to play a role in inflammation.
About the study
Age-related macular degeneration, a major cause of vision loss and blindness, is known to be driven by both genetic and environmental factors. The researchers explored why certain people with genetic risk factors develop the disease while others do not.
“Although considerable effort has been invested in understanding the genes responsible for age-related macular degeneration, variations and mutations in susceptibility genes only increase the risk of developing the disease, but do not cause it,” Dr. Sapieha said in a press release published by Science Daily. “This observation suggests that we must gain a better understanding of how other factors such as environment and lifestyle contribute to disease development.”
In the study, researchers fed mice high-fat diets and later returned them to regular diets, allowing them to regain fitness. They found that even after the mice had recovered a healthy weight and healthy metabolism, they were more susceptible to inflammation in the eye and eventually developed age-related macular degeneration-like lesions.
A person with a BMI (body mass index, a measure of body fat) greater than 30 was associated with progression to late age-related macular degeneration than a person with a lower BMI. However, there are steps you can take to lower your risk and protect your eye health. One large medical study found that a diet rich in fruits and vegetables may decrease the risk of age-related macular degeneration.
Eating fatty fish like salmon, tuna, mackerel, and sardines, which are rich in omega-3 fatty acids, also helps lower the risk of age-related macular degeneration. Colorful fruits, dark leafy vegetables, omega-3 fatty acids, and higher levels of B vitamins can help maintain a healthy weight, which may lead to better eye protection.
About age-related macular degeneration
About 200 million people worldwide are believed to be living with age-related macular degeneration, and that number may reach 288 million by the year 2040. The eye disease mainly affects older adults; one-third of people over age 75 have age-related macular degeneration. While it can be treated, there currently is no cure.
Age-related macular degeneration has two forms, wet and dry. In dry AMD, the most common type, the light-sensitive tissue at the back of the eye, called the macula, gradually becomes damaged. In wet AMD, abnormal blood vessels grow in the back of the eye and damage the macula.
Smoking is a major risk factor for age-related macular degeneration, along with family history and eating a high-fat diet. Dr. Sapieha’s research findings on the role of obesity suggest that maintaining a healthy weight when young can be an important step toward avoiding the disease later in life.
About BrightFocus Foundation
BrightFocus Foundation is a premier nonprofit funder of research to defeat Alzheimer’s, macular degeneration, and glaucoma. Through its flagship research programs—Alzheimer’s Disease Research, National Glaucoma Research, and Macular Degeneration Research—the Foundation is currently supporting a $75 million portfolio of 287 scientific projects. BrightFocus has awarded nearly $300 million in groundbreaking medical research funding since inception and shares the latest research findings, expert information, and English/Spanish disease resources to empower the millions impacted by these devastating diseases. Learn more at brightfocus.org.